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Checking permissions for a shared directory - C #

I want to write code that checks for permissions for a shared directory, I check several solutions, but it works great when trying to get local directory permissions, but when I do test cases for shared directories, it fails.

I am trying to give examples on these issues: SOF: check-for-directory-and-file-write-permets-in-net

but it only works in local directories.

For example, I used this class:

public class CurrentUserSecurity { WindowsIdentity _currentUser; WindowsPrincipal _currentPrincipal; public CurrentUserSecurity() { _currentUser = WindowsIdentity.GetCurrent(); _currentPrincipal = new WindowsPrincipal(WindowsIdentity.GetCurrent()); } public bool HasAccess(DirectoryInfo directory, FileSystemRights right) { // Get the collection of authorization rules that apply to the directory. AuthorizationRuleCollection acl = directory.GetAccessControl() .GetAccessRules(true, true, typeof(SecurityIdentifier)); return HasFileOrDirectoryAccess(right, acl); } public bool HasAccess(FileInfo file, FileSystemRights right) { // Get the collection of authorization rules that apply to the file. AuthorizationRuleCollection acl = file.GetAccessControl() .GetAccessRules(true, true, typeof(SecurityIdentifier)); return HasFileOrDirectoryAccess(right, acl); } private bool HasFileOrDirectoryAccess(FileSystemRights right, AuthorizationRuleCollection acl) { bool allow = false; bool inheritedAllow = false; bool inheritedDeny = false; for (int i = 0; i < acl.Count; i++) { FileSystemAccessRule currentRule = (FileSystemAccessRule)acl[i]; // If the current rule applies to the current user. if (_currentUser.User.Equals(currentRule.IdentityReference) || _currentPrincipal.IsInRole( (SecurityIdentifier)currentRule.IdentityReference)) { if (currentRule.AccessControlType.Equals(AccessControlType.Deny)) { if ((currentRule.FileSystemRights & right) == right) { if (currentRule.IsInherited) { inheritedDeny = true; } else { // Non inherited "deny" takes overall precedence. return false; } } } else if (currentRule.AccessControlType .Equals(AccessControlType.Allow)) { if ((currentRule.FileSystemRights & right) == right) { if (currentRule.IsInherited) { inheritedAllow = true; } else { allow = true; } } } } } if (allow) { // Non inherited "allow" takes precedence over inherited rules. return true; } return inheritedAllow && !inheritedDeny; } }

It checks the permission of the current impersonation for a directory or file. All test cases pass correctly when checking the local directory, but some of them fail in the shared directory, which is the problem I want to solve, so is there any solution for this?

Invalid test case, although the directory did not have write permission:

  [TestMethod] public void HasAccess_NotHaveAccess_ReturnsFalse() { CurrentUserSecurity cus = new CurrentUserSecurity(); bool result = cus.HasAccess(new DirectoryInfo(@"\\sharedpc\readonly"), System.Security.AccessControl.FileSystemRights.Write); Assert.AreEqual(result, false); }
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Your WOMM code. I recommend you figure out why the standard .NET classes fail (in your environment) using the Win32 API to identify any potential problems that BCL is hiding.

Fingers intersect if you try this lower level method, it gives errors to let you know what the problem is with BCL classes or use as a workaround.

 using System; using System.Collections.Generic; using System.Text; using System.Runtime.InteropServices; class MainConsole { [DllImport("Netapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)] static extern int NetShareGetInfo( [MarshalAs(UnmanagedType.LPWStr)] string serverName, [MarshalAs(UnmanagedType.LPWStr)] string netName, Int32 level, out IntPtr bufPtr); [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool GetSecurityDescriptorDacl( IntPtr pSecurityDescriptor, [MarshalAs(UnmanagedType.Bool)] out bool bDaclPresent, ref IntPtr pDacl, [MarshalAs(UnmanagedType.Bool)] out bool bDaclDefaulted ); [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool GetAclInformation( IntPtr pAcl, ref ACL_SIZE_INFORMATION pAclInformation, uint nAclInformationLength, ACL_INFORMATION_CLASS dwAclInformationClass ); [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)] static extern int GetAce( IntPtr aclPtr, int aceIndex, out IntPtr acePtr ); [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)] static extern int GetLengthSid( IntPtr pSID ); [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool ConvertSidToStringSid( [MarshalAs(UnmanagedType.LPArray)] byte[] pSID, out IntPtr ptrSid ); [DllImport("netapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)] static extern int NetApiBufferFree( IntPtr buffer ); enum SID_NAME_USE { SidTypeUser = 1, SidTypeGroup, SidTypeDomain, SidTypeAlias, SidTypeWellKnownGroup, SidTypeDeletedAccount, SidTypeInvalid, SidTypeUnknown, SidTypeComputer } [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] static extern bool LookupAccountSid( string lpSystemName, [MarshalAs(UnmanagedType.LPArray)] byte[] Sid, System.Text.StringBuilder lpName, ref uint cchName, System.Text.StringBuilder ReferencedDomainName, ref uint cchReferencedDomainName, out SID_NAME_USE peUse); [StructLayout(LayoutKind.Sequential)] struct SHARE_INFO_502 { [MarshalAs(UnmanagedType.LPWStr)] public string shi502_netname; public uint shi502_type; [MarshalAs(UnmanagedType.LPWStr)] public string shi502_remark; public Int32 shi502_permissions; public Int32 shi502_max_uses; public Int32 shi502_current_uses; [MarshalAs(UnmanagedType.LPWStr)] public string shi502_path; public IntPtr shi502_passwd; public Int32 shi502_reserved; public IntPtr shi502_security_descriptor; } [StructLayout(LayoutKind.Sequential)] struct ACL_SIZE_INFORMATION { public uint AceCount; public uint AclBytesInUse; public uint AclBytesFree; } [StructLayout(LayoutKind.Sequential)] public struct ACE_HEADER { public byte AceType; public byte AceFlags; public short AceSize; } [StructLayout(LayoutKind.Sequential)] struct ACCESS_ALLOWED_ACE { public ACE_HEADER Header; public int Mask; public int SidStart; } enum ACL_INFORMATION_CLASS { AclRevisionInformation = 1, AclSizeInformation } static void Main(string[] args) { IntPtr bufptr = IntPtr.Zero; int err = NetShareGetInfo("ServerName", "ShareName", 502, out bufptr); if (0 == err) { SHARE_INFO_502 shareInfo = (SHARE_INFO_502)Marshal.PtrToStructure(bufptr, typeof(SHARE_INFO_502)); bool bDaclPresent; bool bDaclDefaulted; IntPtr pAcl = IntPtr.Zero; GetSecurityDescriptorDacl(shareInfo.shi502_security_descriptor, out bDaclPresent, ref pAcl, out bDaclDefaulted); if (bDaclPresent) { ACL_SIZE_INFORMATION AclSize = new ACL_SIZE_INFORMATION(); GetAclInformation(pAcl, ref AclSize, (uint)Marshal.SizeOf(typeof(ACL_SIZE_INFORMATION)), ACL_INFORMATION_CLASS.AclSizeInformation); for (int i = 0; i < AclSize.AceCount; i++) { IntPtr pAce; err = GetAce(pAcl, i, out pAce); ACCESS_ALLOWED_ACE ace = (ACCESS_ALLOWED_ACE)Marshal.PtrToStructure(pAce, typeof(ACCESS_ALLOWED_ACE)); IntPtr iter = (IntPtr)((long)pAce + (long)Marshal.OffsetOf(typeof(ACCESS_ALLOWED_ACE), "SidStart")); byte[] bSID = null; int size = (int)GetLengthSid(iter); bSID = new byte[size]; Marshal.Copy(iter, bSID, 0, size); IntPtr ptrSid; ConvertSidToStringSid(bSID, out ptrSid); string strSID = Marshal.PtrToStringAuto(ptrSid); Console.WriteLine("The details of ACE number {0} are: ", i+1); StringBuilder name = new StringBuilder(); uint cchName = (uint)name.Capacity; StringBuilder referencedDomainName = new StringBuilder(); uint cchReferencedDomainName = (uint)referencedDomainName.Capacity; SID_NAME_USE sidUse; LookupAccountSid(null, bSID, name, ref cchName, referencedDomainName, ref cchReferencedDomainName, out sidUse); Console.WriteLine("Trustee Name: " + name); Console.WriteLine("Domain Name: " + referencedDomainName); if ((ace.Mask & 0x1F01FF) == 0x1F01FF) { Console.WriteLine("Permission: Full Control"); } else if ((ace.Mask & 0x1301BF) == 0x1301BF) { Console.WriteLine("Permission: READ and CHANGE"); } else if ((ace.Mask & 0x1200A9) == 0x1200A9) { Console.WriteLine("Permission: READ only"); } Console.WriteLine("SID: {0} \nHeader AceType: {1} \nAccess Mask: {2} \nHeader AceFlag: {3}", strSID, ace.Header.AceType.ToString(), ace.Mask.ToString(), ace.Header.AceFlags.ToString()); Console.WriteLine("\n"); } } err = NetApiBufferFree(bufptr); } } }

REF: http://blogs.msdn.com/b/dsadsi/archive/2012/03/30/to-read-shared-permissions-of-a-server-resource-in-c-using-netsharegetinfo.aspx

Also, if you can, try the code and this code on a different network, because I think this is an environmental issue.

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Source: https://habr.com/ru/post/1234194/

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